Feeding mechanism for automatic firearms



Feb. 3, 1 953 c, s s 2,627,208

FEEDING MECHANISM FOR AUTOMATIC FIREARMS Original Filed Oct. 29, 1948 3 Sheets-Sheet l Feb. 3, 1953 c. E. SIMPSON 2,627,208

FEEDING MECHANISM FOR AUTOMATIC FIREARMS Original Filed Oct. 29, 1948 5 Sheets-Sheet 2 3 vwcmtm Elnrence E-E!im :& can

Feb. 3, 1953 C. E. SIMPSON FEEDING MECHANISM FOR AUTOMATIC FIREARMS Original Filed Oct. 29, 1948 3 Sheets-Sheet 3 Qwucmfom Ellnreric' E .El'lm]3 5:111

UNITED STATES Patented Feb. 3, 1953 FEEDING MECHANISM FOR AUTOMATIC FIREARMS Original application October 29, 1948, Serial No.

PATENT, OFFICE 1350, Serial No. 154.392

3 Claims. (CL. 89-33) Divided and this application April 6,

(Granted under Title 35, U. S. Code (1952),

see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon. This invention relates to high speed automatic firearms and is particularly directed to improved means for feeding cartridges into position for chambering.

This application is a division of my copending application Serial No. 57,283, filed October 29, 1948, and now matured into Patent No. 2,576,973.

It has been found that the act of advancing a linked belt of cartridges into the feedway of a high speed automatic firearm is best accomplished by a pawl associated with a feed slide arranged to reciprocate transversely of the iongitudinal axis of the gun. Such feed slide is customarily actuated by a pivotal lever Which is in turn operated by a longitudinally reciprocating bolt in such manner that the feeding stroke of the slide occurs during the counter-recoil of the bolt. While such arrangement has performed quite satisfactorily in the past, it does not, however, readily lend itself to such changes as will substantially increase the cyclic rate of fire of the gun.

It is therefore an object of this invention to provide a cartridge feeding structure for a high speed automatic firearm which will eliminate the conventional feed lever cam tracks formed in the bolt.

It is a further object of this invention to provide a cartridge feeding structure wherein the recoil movement of an operating slide will serve to actuate a feed slide for advancing a cartridge into the feedway of a high speed automatic firearm.

Moreover, in those firearms having a transverse feedway located in a higher vertical plane than the bore axis of the barrel, the cartridge feeding cycle must include the step of transferring individual cartridges from the surface of the feedway to a position within the receiver whereby chambering can be readily accomplished by the bolt during its counter-recoil stroke. Most firearms of this type utilize an extractor or similar gripping device associated with the bolt for holding the cartridges during movement from the feedway to the chamber of the barrel. Such gripping devices customarily engage only a small portion of the annular extracting groove provided day automatic firearms, it is highly desirable that movement of the cartridge prior to chambering be reduced to a minimum. It is also important that the longitudinal axis of the cartridge be aligned as closely as possible with the bore axis of the barrel and furthermore that such cartridge be adequately supported prior to and duringits chambering movement in order that objectionable tilting or wavering of the bullet will be eliminated.

Accordingly, it is a further object of this invention to provide in a high speed automatic firearm a feeding construction which entirely eliminates the necessity for withdrawing a cartridge from the top surface of the feedway in order to position it in front of a counter-recoiling bolt.

It is another object of this invention to provide stationary means for supporting a cartridge in a firearm receiver immediately prior to and during the chambering movement thereof.

It is a particular object of this invention to provide cartridge supporting means for an automatic firearm which will adequately position and hold a cartridge for chambering during counterrecoil of the firearm and yet permit ejection of a fired cartridge case during recoil.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a longitudinal cross-sectional view of a firearm embodying the structure of the present invention and showing the operating parts in the firing position;

Fig. 2 is a view similar to Fig. 1 but showing the operating parts in the fully recoiled position;

Fig. 3 is a side view of one of the cartridge support rods of this invention;

Fig. 4 is a rear view of the bolt showing the cartridge support rods in a cartridge-engaging position;

Fig. 5 is a view similar to Fig. 4 but showin the cartridge support rods in position to permit ejection of a fired cartrid e case;

Fig. 6 is an enlarged cross-sectional view of the bolt showing the extractor and ejector associated therewith;

Fig. 7 is a top View of the receiver with the cover removed;

Fig. 8 is a top schematic view of the lever arrangement utilized for transversely feeding a belt of cartridges through the feedwa-y of the firearm;

Fig. 9 is a side view of the parts shown in Fig. 8; and

Fig. is a top view of the operating slide.

Referring to the drawings there is illustrated in Figs. 1 and 2 a portion of the firearm in which the present invention is embodied. The firearm essentially comprises a receiver 5 to the front end of which a barrel 6 having a cartridge chamber 38 is fixedly secured as by threads 1, a bolt 8 arranged to reciprocate in receiver 5, and an operating slide 9 mounted beneath bolt 8 and also arranged to reciprocate within receiver 5 in a manner more fully disclosed in my copending application, Serial No. 57,283, filed October 29, 1948.

Receiver 5 is provided with a transverse feedway Hi and a cover I! is pivotally and releasably secured to receiver 5 above feedway it. A vertical slot-like opening [2. of sufficient size to freely accommodate a cartridge i3 is centrall provided down through feedway If). A cartridge belt feed slide M is slidably mounted within a depending bracket 39 integrally formed on the underside of cover ll and is arranged to be actuated by a pivotal belt feed lever IE to advance cartridges I3 along feedway l0.

One end of lever i5 is arcuately formed and is engaged in a suitable symmetrical recess it! provided in the top of belt feed slide it as best shown in Fig. 8, while the other end is pivotally secured at 4| to a depending lug 32 formed on the underside of cover i 1 adjacent the front end thereof. Lever i5 is also provided with an integral portion 43 extending beyond the pivot point 4| at an obtuse angle thereto. A substantially U-shaped opening M is formed in the outer end of lever portion &3 and is arranged to receive the rounded end of a second lever d5. A vertically disposed shaft 46 is rotatably mounted in one of a pair of holes 41 extending vertically through receiver 5 on either side of cartridge opening 12. Shaft serves as a connecting member between lever 45 and another lever 48 fixedly secured to the bottom end of shaft $6. This last lever 58 is provided with a rounded end 49 arranged to engage in a cam groove 55 extending longitudinally along the side of operating slide 9. An identical cam groove 5! is also disposed along the opposite side of slide 9 so that if desired, belt feed lever l5 can be arranged to feed cartridges 13 into feedway H) from the opposite side of the gun. This is accomplished by reversing lever so that opening 44 therein faces in the opposite direction and mounting shaft 46 in the other of receiver holes 41. The position of slide 40 is "also reversed so that recess 40 therein will be engaged by the arcuate end of lever 15 in the same manner as when feeding in the opposite direction. Consequently, lever 48 will engage in the opposite cam groove 5| and lever 45 will engage in opening 44 of lever 15 thereby actuating feed slide It in a direction opposite that shown in Figs. 8 and 9. When operating slide 9 recoils upon the discharge of cartridge I3, cam groove 50 therein actu-ates lever 48 to rotate shaft 46 accordingly. This movement of shaft 46 causes lever 45 to pivot feed lever l5 and thereby transmit feeding movement to slide M. Upon counterrecoil of operating slide 9, belt feed slide I 4 is moved outwardly of the gun to engage the next cartridge l3.

Bolt 8 comprises a cylindrical body portion l5 terminating in a depending rectangular base portion 11 arranged to be slidably engaged in receiver 5. Bolt 8 is positioned below vertical opening 12 and in line with the longitudinal axis thereof so that when a cartridge I3 is forced through opening [2 by suitable means (not shown) the base thereof will be in axial alignment with the cylindrical face of bolt 8 and in position to be rammed into chamber 38 upon the counter-recoil movement thereof.

On the underside of the front portion of bolt 8 there is provided a slot I8 of suitable width to accommodate an extractor IS. A rectangular recess extends vertically upward in bolt 3 and intersects slot I 8. Recess 20 receives a transverse lug 2| extending upwardly from extractor [9. A' pin 22 is suitably interposed between the forward surface of lug 2i and the front wall surface of rectangular recess 20. Consequently pin 22 pivotally secures extractor 19 within slot I8. A spring 23 seated between the rear end portion of extractor l 9 and the bottom of bolt 8 is arranged to bias the forward end of extractor IQ into engagement with the rim of a cartridge It so as to normally hold the base thereof against a suitable cartridge seating recess 24 formed in the front face of bolt 8. A spring-biased plunger 25 is seated in bolt 8 as shown in Fig. 6 with the forward end protruding suificiently therefrom to serve as an ejector in a manner to be described.

The rectangular base portion I1 of bolt 8 is provided with a pair of spaced apart parallel holes 26 extending longitudinally therethrough. Passing through each of holes 26 and freely rota-table therein is a cartridge supporting rod 21. The rear ends of rods 21 are arranged to be rotatably supported in a back plate portion 28 of receiver 5. The front end of each of rods 21 is of reduced diameter as shown at 29 in Fig. 3 and is arranged to .be rotatably mounted in suitable recess-es (not shown) which are located in the forward portion of receiver 5. Each rod 21 is provided with a cam slot 30 extending longitudinally along the outer side thereof. Cam slot 30 is provided with a portion of reduced width as shown at 3| in Fig. 3 which extends forwardly from the rear end to a point where a forwardly inclined camming shoulder 32 is formed on the upper side of slot30. Cam slot 30 continues along rod 21 until the normal width thereof is reduced to that shown at 33 by a second camming shoulder 34 similarly inclined but located on the side of slot 3!! opposite that of shoulder 32. A stud 36 fixedly secured in either side of bolt 8 is arranged to extend into hole 26 and engage in cam slot 30. The bottom of cam slot 30 is curved as best shown at to provide clearance for the end of stud 35 during the rotary movement of rod 21. The side of each of rods 21 opposite to that of cam slots 30 is flattened for a substantial portion as best indicated at 31 in Figs. 4 and 5.

When the flattened portions 31 of rods 21 are inclined towards one another as in Fig. 4, the space therebetween is slightly less than the diameter of cartridge 13 and accordingly such rods 21 serve as a support therefor. When bolt 8 is in the battery position of Fig. 1, rods 21 are disposed so that the fiattened portions 31 are parallel to one another and thereby provide an open ing therebetween slightly greater than the diam eter of a cartridge [3. Such position of rods 21 is maintained until studs 35 contact camming shoulders 32 toward the end of bolt recoil. When a fired cartridge case is extracted from the chamber 38 of barrel 6 by means of extractor l9, ejector plunger 25 will pivot the case about its point of contact with extractor I-9 and cause the case to be ejected down through receiver 5 between rods 27. However, when stud 36 on bolt 8 strikes shoulder 32, rods 21 will be rotated to the position disclosed in Fig. 4. Thus rods 2'! are now arranged to receive and support the succeeding cartridge 13 immediately prior to and during chambering thereof. It will be noted that the longitudinal axis of supported cartridge it is centrally located with respect to the transverse axis of barrel chamber 38 and parallel to the axial center thereof although at a slight vertical distance therebelow. .Thus as bolt 3 counterrecoils, cartridge is is rammed into chamber 38 with a minimum of vertical tilting and no transverse movement. As the sides of the bullet of cartridge 13 strike the walls of chamber 38, the case automatically centers itself to seat perfectly in chamber 38 without any possibility of the stubbing and jamming frequently encountered in those firearms in which the cartridges are supported at the base only. When studs 3% strike camming shoulders 34, rods 21 are rotated to permit the ejection of the fired cases upon recoil as previously explained. Thus by utilizing the operating slide of a firearm to actuate the cartridge feed mechanism, the conventional feed track in the bolt can be eliminated. As a result, both the size and weight of the bolt can be decreased without detracting from the strength thereof. Such reduction, of course, permits a desirable increase in the rate of fire of the gun. In addition, the cartridge feeding mechanism here disclosed takes advantage of the increased power existing in the recoil movement of the operating members as compared to the counterrecoil movement thereof. By actuating a feed slide so as to advance a belt of cartridges into a gun feedway on the power stroke, a further increase in the rate of fire is readily attained in comparison to a feeding movement which occurs during the counter-recoil stroke of the operating members.

Moreover, the construction of the present invention permits the cartridges i3 to be fed into position in front of bolt 8 simply by pushing the cartridges downwardly through opening I? in feedway it by means of suitable mechanism (not shown). This is in distinct contrast to the more complicated procedure of other feeding structures wherein the cartridges must be rst withdrawn from along the feedway and then cammed or tilted so that the base thereof will be disposed in front of the recoiling bolt. Prior art feeding constructions were limited to such requirements inasmuch as any support means positioned beneath the cartridges would interfere with ejection of the fired case. However, by means of the novel cartridge support rods of this invention, such limitations are no longer applicable and the simple yet reliable structure herein described can be readily employed for effective cartridge feeding.

I claim:

1. In an automatic firearm having a receiver and a bolt reciprocable therein, the combination of, a pair of cartridge support rods extending 1ongitudinally through the bolt and rotatably secured at either end in the receiver, each of said rods having a cam track on the outer side thereof and a longitudinal fiat surface on the inner side thereof, and means in the bolt engageable in said cam tracks for rotating said rods from a cartridge supporting position wherein said fiat surfaces are inclined toward one another to a cartridge releasing position wherein said flat surfaces are parallel to one another.

2. In an automatic firearm having a receiver and a bolt reciprocable therein, the combination of, a pair of cartridge support rods extending longitudinally through the bolt and rotatably secured at either end in the receiver, each of said rods having a longitudinal cam track disposed along the outer side thereof and a longitudinal flat surface along the inner side thereof, said flat surfaces being slightly greater than the length of a cartridge, a first camming shoulder located adjacent the rear end of said cam track on the upper side thereof, a second camming shoulder on the lower side of said cam track located forwardly of said first shoulder, and a stud fixedly secured in either side of the bolt and arranged to engage in said cam track whereby said studs contact said first camming shoulders during recoil of the bolt to rotate said rods to a position wherein said fiat surfaces are inclined toward one another for supporting a cartridge thereon and whereby said studs contact said second camming shoulders during counter-recoil of the bolt to rotate said rods to a position wherein said fiat surfaces are parallel to one another and permit a cartridge to pass downwardl therethrough.

3. In an automatic firearm having a receiver and a barrel extending forwardly therefrom, the combination of, a cartridge feedway transversely disposed in the receiver above the plane of the barrel, said feedway having a centrally located cartridge opening extending vertically therethrough, a cylindrical bolt having a rectangular base portion slidably mounted in the receiver for reciprocating movement, said base portion having a longitudinal hole therethrough located on either side of said cylindrical portion, a cartridge support rod disposed in each of said holes and rotatably secured at either end in the receiver, each of said rods having a cam track on the outer side thereof and a longitudinal flat surface on the inner side thereof, and a stud fixedly secured in either side of said bolt and arranged to extend into said longitudinal hole to engage in said cam track whereby recoil movement of said bolt cams said rods to a position wherein said fiat surfaces are inclined toward one another for supporting a cartridge upon exit from said vertical cartridge opening in said feedway and whereby counter-recoil movement of said bolt cams said rods to a position wherein said fiat surfaces are parallel to each other and spaced apart at a distance slightly greater than the diameter of a cartridge case for permitting ejection thereof downwardly through the receiver.

CLARENCE E. SIMPSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,168,199 Gebauer Aug. 1, 1939 FOREIGN PATENTS Number Country Date 193,379 Switzerland Jan. 17, 1938 897,534 France Mar. 23, 1945 

